Percutaneous compression and distraction system

ABSTRACT

The present invention provides a compression and distraction shaft assembly used to apply compression and distraction to bones including vertebrae. Shaft A assembly and shaft B assembly are attached together via a polyaxial fulcrum. The polyaxial fulcrum allows all rotational degrees of freedom between shaft A assembly and shaft B assembly. Such fulcrum, during compression and distraction, does not impart ancillary stresses or motion to vertebrae. An hourglass-shaped bore for engaging pliers is formed in approximately middle of both the shaft A assembly and the shaft B assembly. Distraction pliers having cylindrical tips are used to apply distraction to vertebrae. Once handles are pressed to impart an appropriate amount of distraction to the vertebrae, they are locked in this position. Compression pliers having cylindrical tips are used to apply compression to vertebrae. Once handles are pressed to impart an appropriate amount of compression to the vertebrae, they are locked in this position.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/547,482, filed Nov. 19, 2014, which is a continuation ofU.S. patent application Ser. No. 13/942,071, filed Jul. 15, 2013, whichis a continuation of U.S. patent application Ser. No. 13/419,919, filedMar. 14, 2012, which is a continuation of U.S. patent application Ser.No. 11/904,030, filed Sep. 25, 2007, which claims the benefit of thefiling date of U.S. Provisional Patent Application No. 60/847,174, filedSep. 25, 2006, the disclosures of which are hereby incorporated hereinby reference.

BACKGROUND OF THE INVENTION

The present invention relates to a percutaneous compression anddistraction system, more particularly to a system for percutaneouscompression or distraction of vertebral bodies via pedicle screws.

BRIEF DESCRIPTION OF THE PRIOR ART

Various compression pliers and distraction devices are available toimpart compression or distraction forces to bones. However, thesedevices fail to allow for all rotational degrees of freedom so as to notover constrain the desired compression or distraction motion andtherefore fail to function appropriately when the trajectories of thecompression and distraction shafts are non-coplanar. Therefore, there isa need for a compression and distraction system that provides apolyaxial fulcrum point that does not over constrain the motion and atthe same time provides high mechanical advantage during compression anddistraction of vertebral elements.

SUMMARY OF THE INVENTION

The present invention provides a compression and distraction shaft Aassembly and a compression and distraction shaft B assembly. An assemblyof the shaft A assembly and shaft B assembly forms a compression anddistraction shaft assembly used to apply compression and distraction tobones including vertebrae. Shaft A assembly and shaft B assembly areattached together in use via a polyaxial fulcrum. The polyaxial fulcrumallows all rotational degrees of freedom between shaft A assembly andshaft B assembly. Such fulcrum, during compression and distraction, doesnot impart ancillary stresses or motion to vertebrae. Anhourglass-shaped bore for engaging pliers is formed in approximatelymiddle of both the shaft A assembly and the shaft B assembly.

Distraction pliers having cylindrical tips are used to apply distractionto vertebrae. The tips of the distraction pliers are inserted inhourglass-shaped bores and handles of the pliers pressed together tomove the tips away from each other. This results in distraction of thevertebrae that are connected to the arcuate-shaped end of the shaft Aassembly and shaft B assembly. Once handles are pressed to impart anappropriate amount of distraction to the vertebrae, they are locked inthis position.

Compression pliers having cylindrical tips are used to apply compressionto vertebrae. The tips of the compression pliers are inserted inhourglass-shaped bores and handles of the pliers pressed together tomove the tips towards each other. This results in compression of thevertebrae that are connected to the arcuate-shaped end of the shaft Aassembly and shaft B assembly. Once handles are pressed to impart anappropriate amount of compression to the vertebrae, they are locked inthis position.

An object of the preset invention is to provide a bone compressionsystem having a first shaft and a second shaft. The first shaft has afirst end and the second shaft has a second end. The first shaft isadapted to engage with an attachment to a first bone and the secondshaft adapted to engage with an attachment to a second bone. The systemincludes compression pliers for compressing together the first shaft andthe second shaft. The compression pliers engage the first shaft and thesecond shaft such that the first shaft and the second shaft can move inall directions independent of each other.

Another object of the invention is to provide a bone distraction systemhaving a first shaft and a second shaft. The first shaft has a first endand the second shaft has a second end. The first end of the first shaftand the second end of the second shaft are adapted to mate with eachother to provide a polyaxial fulcrum point about which the first shaftand the second shaft articulate. The system also includes distractionpliers for distracting the first shaft and the second shaft from eachother. The distraction pliers engage the first shaft and the secondshaft such that the movement of the polyaxial fulcrum is not restrictedby the distraction pliers.

Another object of the invention is to provide a bone compression anddistraction system that includes all the components of the bonecompression and bone distraction system described above.

Another object of the invention is to provide a method of compressing ordistracting vertebral bodies. The method includes providing a firstpedicle screw, a second pedicle screw, a compression and a distractiondevice. The compression and the distraction device each have a firstshaft having a first end and a second end and a second shaft having athird end and a fourth end. The first end of the first shaft and thethird end of the second shaft are mated with each other to provide apolyaxial fulcrum point about which the first shaft and the second shaftarticulate. The second end of the first shaft and the fourth end of thesecond shaft are engaged with the first pedicle screw and the secondpedicle screw respectively. Compression pliers or distraction pliers areengaged with the first shaft and the second shaft, and the vertebrae arecompressed or distracted by operating the pliers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of compression and distraction shaft Asubassembly.

FIG. 1A and 1B are side views of the shaft A subassembly.

FIG. 2 is a side view of the shaft of FIG. 1.

FIG. 2A is a top view of the shaft of FIG. 1.

FIG. 2B is a sectional view along line A-A of shaft of FIG. 1.

FIG. 3 is an isometric view of compression and distraction shaft Bsubassembly.

FIG. 3A and 3B are side views of the shaft B subassembly.

FIG. 4 is a side view of the shaft of FIG. 3.

FIG. 4A is a top view of the shaft of FIG. 3.

FIG. 4B is a sectional view along line A-A of shaft of FIG. 3.

FIG. 5 shows compression pliers engaged with compression distractionshafts.

FIG. 5A also shows compression pliers engaged with compressiondistraction shafts.

FIG. 6 shows distraction pliers engaged with compression distractionshafts.

FIG. 6A also shows distraction pliers engaged with compressiondistraction shafts.

FIG. 7 is an assembly drawing showing a distraction pliers assembly.

FIG. 7A shows details of the distraction pliers assembly of FIG. 7.

FIG. 8 is an assembly drawing of a compression pliers assembly.

FIG. 8A shows details of the compression pliers assembly of FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1, 1A and 1B show a compression and distraction shaft A assembly20. FIGS. 3, 3A and 3B show a compression and distraction shaft Bassembly 22. A further assembly of the shaft A assembly 20 and shaft Bassembly 22 forms a compression and distraction shaft assembly 24 seenin FIGS. 5, 5A, 6 and 6A.

Assembly 20 includes a shaft 26. FIG. 2 shows the details ofconstruction of shaft 26. Shaft 26 has two long plates 28 attached to itin diametrically opposed location. One end of each of the plates 28overhangs from the first end 30 of shaft 26. The overhanging portionsare located opposite each other and have an arcuate shape at the verytip. The arcuate shape allows shaft 26 to lay over a rod that may beimplanted on the vertebrae.

A tab 32 is attached in approximately middle of shaft 26. Tab 32 has abore 34. Bore 34 has an hourglass shape along its central axis. A secondend 36 of shaft 26 is on the opposing side from end 30. A fulcrum 38 isattached at second end 36. The means for attaching fulcrum 38 may be abore 40 formed in shaft 26 and bore 42 formed in fulcrum 38 with a pindriven through bores 40 and 42 to connect fulcrum 38 to shaft 26.

Assembly 22 includes a shaft 44. FIGS. 4, 4A and 4B show the details ofconstruction of shaft 44. Shaft 44 has a first end 46 and a second end48. First end 46 is similar in construction to first end 30 of shaft 26.Shaft 44 has two long plates 50 attached to it in diametrically opposedlocation. One end of each of the plates 50 overhangs from the first end46 of shaft 44. The overhanging portions are located opposite each otherand have an arcuate shape at the very tip. The arcuate shape allowsshaft 44 to lay over a rod that may be implanted on a vertebrae.

A tab 52 is attached in approximately middle of shaft 44. Tab 52 has abore 54. Bore 54 has an hourglass shape along its central axis. A ball56 is formed at second end 48. Ball 56 mates with fulcrum 38 to form apolyaxial fulcrum point. When shaft 26 and shaft 44 are assembled byinserting ball 56 in fulcrum 38 a poly axial fulcrum that allows allrotational degrees of freedom is formed. Such fulcrum, duringcompression and distraction, does not impart ancillary stresses ormotion to vertebrae.

FIGS. 7 and 7A show distraction pliers 60. Distraction pliers 60 have afirst handle 62 and a second handle 64. First handle 62 has a tip end 66and a ratchet end 68. First handle 62 has an elongate shape with acylindrical tip 70 formed at tip end 66. At a distance below tip end 66two tabs 72 and 74 extend from the body of first handle 62. Tabs 72 and74 are parallel to each other and have a bore 75 formed through them.The handle end opposing tip end 66 also has two tabs 76 and 78 extendfrom the body of first handle 62. A bore 80 is formed through tabs 76and 78. A screw hole 82 is formed at a distance from the ratchet end andabove tabs 76 and 78. A leaf spring 84 is attached to first handle 62 byinserting a screw 86 in a hole in leaf spring 84 and threading screw 86in screw hole 82. Leaf spring 82 has a far end that projects away fromfirst handle 62. The far end has a notch 88 formed at its tip. A ratchet89 is attached to ratchet end 68 of the first handle 62. The ratchet 89has a bore 91 that aligns with bore 80 in tabs 76 and 78. A pin 93 isdriven through bores 80 and 91 to attach ratchet 89 to first handle 62.Ratchet 89 has triangular projections formed on its surface.

Second handle 64 has a tip end 92 and a ratchet end 94. Second handle 64has an elongate shape with a cylindrical tip 90 formed at tip end 92. Ata distance below tip end 92 a tab 96 extends from the body of secondhandle 64. Tab 96 has a bore 98 formed through it. A leaf spring 100 isattached to second handle 64. Second handle 64 has two screw holes (notshown) formed above the ratchet end 94. Leaf spring 100 is attached tosecond handle 64 by threading two screws 102 and 104 via two holes inleaf spring 100 and into the screw holes in second handle 64. Leafspring 100 has a far end that projects away from first handle 64. Leafspring 100 has notch 108 formed at its tip. Notch 108 engages notch 88thereby engaging leaf springs 84 and 100. When engaged, leaf springs and100 keep the distraction pliers biased in a closed position. A tooth 106is formed at the tip of ratchet end 94. First handle 62 and secondhandle 64 are rotatably joined together by aligning bores 75 and 80 andinserting a screw 108 through them.

In use, cylindrical tips 70 and 90 are inserted in hourglass-shapedbores 34 and 54 and first handle 62 and second handle 64 pressedtogether. When the first handle 62 and the second handle 64 are pressedtogether, the cylindrical tip 70 and 90 are moved away from each other.This results in distraction of the vertebrae that are connected to thearcuate-shaped end of the shaft A assembly 20 and shaft B assembly 22.The connection between the arcuate end of the shaft assemblies 20 and 22and the vertebrae may be made in any known manner. For example, each ofthe shaft assemblies 20 and 22 may be connected to a cup of a pediclescrew mounted on the vertebra via a latch or a threaded connection. Oncefirst handle 62 and second handle 64 are pressed to impart anappropriate amount of distraction to the vertebrae, they are locked inthis position. Tooth 106 engages ratchet 89 to lock first handle 62 andsecond handle 64 in their pressed position, thereby holding thevertebrae in a distracted position while the surgeon fixes a rod in thepedicle screws.

FIGS. 8 and 8A show compression pliers 110. Compression pliers 110 havea third handle 112 and a fourth handle 114. Third handle 112 has a tipend 116 and a ratchet end 118. A cylindrical tip 120 is formed at tipend 116. A hole 122 is formed in the body of third handle 112 below tipend 116. The end of third handle 112 opposing tip end 116 has two tabs124 and 126. A bore 128 is formed through tabs 124 and 126. A screw hole130 is formed in body of third handle 112 above tabs 124 and 126. A leafspring 132 is attached to third handle 112 by inserting a screw 134 in ahole 136 formed in leaf spring 132 and threading the screw in the hole130. Leaf spring 132 has a far end that projects away from third handle112. The far end has a notch 138 formed at its tip. A ratchet 140 isattached to ratchet end 118 of the third handle 112. The ratchet 140 hasa bore 142 that aligns with bore 128 in tabs 124 and 126. A pin 144 isdriven through bores 128 and 142 to attach ratchet 140 to third handle112. Ratchet 140 has triangular projections formed on its surface.

Fourth handle 114 has a tip end 146 and a ratchet end 148. Fourth handle114 has a cylindrical tip 150 formed at tip end 146. At a distance belowtip end 146 a bore 152 is formed in the body of third handle 114. A leafspring 154 is attached to fourth handle 114. Fourth handle 114 has twoscrew holes (not shown) formed above the ratchet end 148. Leaf spring154 is attached to fourth handle 114 by threading two screws 156 and 158via two holes in leaf spring 154 and into the screw holes in fourthhandle 114. Leaf spring 154 has a far end that projects away from fourthhandle 114. Leaf spring 154 has notch 160 formed at its tip. Notch 160engages notch 138 thereby engaging leaf springs 154 and 132. Whenengaged, leaf springs 132 and 154 keep the compression pliers biased inan open position. A tooth 162 is formed at the tip of ratchet end 148.Third handle 112 and fourth handle 114 are rotatably joined together byaligning bores 122 and 152 and inserting a screw 164 through them.

In use, cylindrical tips 120 and 150 are inserted in hourglass-shapedbores 34 and 54 and third handle 112 and fourth handle 114 pressedtogether. When the third handle 112 and fourth handle 114 are pressedtogether, cylindrical tips 120 and 150 are moved towards each other.This results in compression of the vertebrae that are connected to thearcuate-shaped end of the shaft assembly 20 and shaft assembly 22. Theconnection between the arcuate end of the shaft assemblies 20 and 22 andthe vertebrae may be made in any known manner. For example, each of theshaft assemblies 20 and 22 may be connected to a cup of a pedicle screwmounted on the vertebrae via a latch or a threaded connection. Oncethird handle 112 and fourth handle 114 are pressed to impart anappropriate amount of compression to the vertebrae, they are locked inthis position. Tooth 162 engages ratchet 140 to lock third handle 112and fourth handle 114 in their pressed position, thereby holding thevertebrae in compressed position while the surgeon fixes a rod in thepedicle screws.

The compression and distraction pliers may also be used with compressiondistraction shafts that are not attached to each other. These shafts canbe attached rigidly to the tips of the compression or distraction pliersand impart compression or distraction to the bones. The compression anddistraction system may also be used with minimally invasive surgery asdescribed, for example, in commonly assigned U.S. Patent ApplicationPublication No. 2007/0233079, entitled “Rod Contouring Apparatus AndMethod For Percutaneous Pedicle Screw Extension,” which is incorporatedherein by reference in its entirety.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. A method of displacing vertebral bodies, comprising: removablyengaging a displacement device to a first shaft and a second shaft, thefirst shaft having a distal end and a proximal end and a longitudinalaxis extending therebetween, the distal end of the first shaft beingremovably connected to a first pedicle screw mounted to a first vertebraof a spine, and the second shaft having a distal end and a proximal endand a longitudinal axis extending therebetween, the distal end of thesecond shaft being removably connected to a second pedicle screw mountedto a second vertebra of the spine, the displacement device being engagedto the first and second shafts proximally of their respective distalends; and squeezing a first handle and a second handle of thedisplacement device towards one another to impart forces to the firstand second shafts so as to displace the first and second vertebrae withrespect to one another, the first and second handles extending laterallywith respect to the longitudinal axes of the first and second shafts. 2.The method of claim 1, wherein the step of removably engaging adisplacement device to the first shaft and the second shaft comprises:removably engaging the displacement device to a central portion of thefirst shaft intermediate the proximal and distal ends of the firstshaft; and removably engaging the displacement device to a centralportion of the second shaft intermediate the proximal and distal ends ofthe second shaft.
 3. The method of claim 1, wherein the displacement ofthe first and second vertebrae with respect to one another comprisescompression of the first and second vertebrae towards one another. 4.The method of claim 1, wherein the displacement of the first and secondvertebrae with respect to one another comprises distraction of the firstand second vertebrae apart from one another.
 5. The method of claim 1,wherein the step of removably engaging the displacement device to thefirst shaft and the second shaft comprises: removably engaging thedisplacement device to a connector of the first shaft; and removablyengaging the displacement device to a connector of the second shaft. 6.The method of claim 5, wherein the step of removably engaging thedisplacement device to the connector of the first shaft comprisesinserting a portion of the displacement device into an opening of theconnector of the first shaft, and wherein the step of removably engagingthe displacement device to the connector of the second shaft comprisesinserting a portion of the displacement device into an opening of theconnector of the second shaft.
 7. The method of claim 1, furthercomprising providing a second displacement device, wherein thedisplacement device is adapted to compress the first and secondvertebrae towards one another in response to squeezing the first andsecond handles of the displacement device towards one another, andwherein the second displacement device is adapted to distract the firstand second vertebrae apart from one another.
 8. The method of claim 7,wherein the second displacement device has a first handle and a secondhandle, the second displacement device being adapted to distract thefirst and second vertebrae apart from one another in response tosqueezing the first and second handles of the second displacement devicetowards one another.
 9. The method of claim 1, further comprisingconnecting the proximal end of the first shaft to the proximal end ofthe second shaft.
 10. The method of claim 9, wherein the step ofconnecting the proximal end of the first shaft to the proximal end ofthe second shaft comprises providing a fulcrum proximate the proximalends of the first and second shafts about which the first shaft and thesecond shaft are pivotable with respect to one another.
 11. The methodof claim 1, wherein the step of squeezing the first and second handlestowards one another comprises pivoting the first and second handlestowards one another about a pivot point of the displacement device. 12.The method of claim 11, wherein the step of removably engaging thedisplacement device to the first shaft and the second shaft comprises:removably engaging a first tip end of the displacement device to thefirst shaft; and removably engaging a second tip end of the displacementdevice to the second shaft; wherein the first and second tip ends of thedisplacement device are at an opposite side of the pivot point of thedisplacement device from the first and second handles.
 13. The method ofclaim 1, further comprising: connecting the distal end of the firstshaft with the first pedicle screw; and connecting the distal end of thesecond shaft with the second pedicle screw.
 14. The method of claim 13,further comprising: inserting the first pedicle screw in the firstvertebra; and inserting the second pedicle screw in the second vertebra.15. The method of claim 1, wherein the displacement device includes alinear ratchet.
 16. The method of claim 1, wherein the step of removablyengaging the displacement device to the first shaft and the second shaftcomprises inserting a portion of the displacement device into an openingof the first shaft.
 17. The method of claim 16, wherein the step ofinserting a portion of the displacement device into the opening of thefirst shaft comprises inserting a cylindrical extension of thedisplacement device into the opening of the first shaft.
 18. The methodof claim 17, wherein the cylindrical extension of the displacementdevice is at a distal end of the displacement device, opposite the firstand second handles.
 19. The method of claim 1, wherein the displacementdevice includes a linear member extending between and connecting thefirst and second handles.
 20. The method of claim 19, wherein the linearmember is a ratchet configured to lock the position of the first andsecond handles after the step of squeezing the first and second handlestowards one another, so as to restrain the first and second handles frommoving apart from one another.
 21. A method of displacing vertebralbodies, comprising: connecting a distal end of a first shaft to a firstpedicle screw mounted to a first vertebra of a spine, the first shafthaving a longitudinal axis extending therealong; connecting a distal endof a second shaft to a second pedicle screw mounted to a second vertebraof the spine, the second shaft having a longitudinal axis extendingtherealong; removably engaging a displacement device to the first shaftand the second shaft proximally of their respective distal ends suchthat a first handle and a second handle of the displacement deviceextend laterally with respect to the longitudinal axes of the first andsecond shafts; and squeezing the first and second handles towards oneanother to impart forces to the first and second shafts so as todisplace the first and second vertebrae with respect to one another.